1. FIELD OF THE INVENTION
This invention relates to oil soluble additive mixtures useful in fuel and lubricating oil compositions, including concentrates containing said additives, and methods for their manufacture and use. The additive mixture comprises an ashless non-borated dispersant, copper antioxidant, and friction modifiers having improved storage stability.
2. DESCRIPTION OF THE PRIOR ART
Heretofore, many lubricants and fuels have contained compounds known as friction modifiers (also termed "lubricity additives"), which act to reduce the friction of internal engine parts and thereby increase fuel economy. U.S. Pat. No. 3,429,817 relates to the improvement of the lubricity and load carrying ability of a synthetic ester lubricating oil by addition of an ester formed by reacting about 2 moles of C.sub.2 to C.sub.5 glycol with about 1 mole of C.sub.36 dicarboxylic acid dimer of a C.sub.18 unsaturated fatty acid (e.g., linoleic acid or oleic acid). U.S. Pat. No. 3,273,981 is directed to fuels and lubricating oil containing as lubricating additive a mixture of dimer acids and polyhydric alcohol partial esters. U.S. Pat. No. 4,459,223 relates to lubricating oil friction reducing additives which are the reaction product of a dimer carboxylic acid (e.g., linoleic acid dimers) and a polyhydric alcohol having at least 3 hydroxyl groups. U.S. Pat. No. 4,479,883 relates to lubricating oil compositions having a relatively low level of phosphorous and improved friction reducing properties by use of a mixture of a glycol or glycerol ester of a polycarboxylic acid (e.g., linoleic acid dimers) with Mo, Zn, or Sb dithiocarbamates. U.S. Pat. No. 4,557,846 relates to lubricating oil friction reducing additives comprising oil soluble hydroxyamide compounds prepared by condensing a dimer carboxylic acid (e.g., linoleic acid dimers) with a hydroxyamine U.S. Pat. No. 4,617,026 relates to fuel friction modifying additives comprising hydroxyl-containing esters of a C.sub.12 to C.sub.30 monocarboxylic acid and a glycol or trihydric alcohol, wherein the glycol can comprise polyalkylene glycols having 2 to 100 oxyalkylene repeat units. U.S. Pat. No. 4,683,069 relates to lubricating oil fuel economy additives comprising glycerol partial esters of C.sub.16 -C.sub.18 fatty acids.
The instability, and hence the need for a stabilization of, compositions containing polycarboxylic acid-glycol esters, ashless dispersant and certain metal lubricating oil additives has been noted in the art. U.S. Pat. No. 4,105,571 is directed to storage stable lubricating compositions having improved anti-friction and anti-wear properties containing a zinc dihydrocarbyldithiophosphate, an ester of a polycarboxylic acid and a glycol, and an ashless high molecular weight dispersant, wherein either the zinc or ester component, or both, are predispersed with the ashless dispersant prior to adding them to the lubricating composition. The friction modifying esters are disclosed to include linoleic acid dimers which are esterified with glycol such as diethylene glycol.
U.S. Pat. No. 4,388,201 discloses lubricating oil compositions containing such polycarboxylic acid-glycol friction modifier esters in combination with borated or non-borated alkenyl succinimide dispersants, by the addition of small proportions of a co-dispersant comprising an oil-soluble hydrocarbyl substituted mono- or bis-oxazoline or lactone oxazoline.
U.S. Pat. No. 4,505,829 discloses lubricating oil compositions containing polycarboxylic acid, glycol esters as friction modifiers in combination with hydrocarbon soluble alkenyl succinimide dispersants with reduced tendency towards formation of sediment upon storage. The storage stability is improved by the addition thereto of small proportions of polyol or polyol anhydride partial esters of a fatty acid or an ethoxylated fatty acid, amine or amide compound.
U.S. Pat. No. 4,617,134 relates to storage stable lubricating oil compositions comprising an additive combination of a polycarboxylic acid glycol or glycerol ester, as friction modifier, and zinc dihydrocarbyldithiophosphate and an ashless dispersant containing a selected amount of free hydroxyl groups.
U.S. Pat. No. 4,684,473 relates to solubilization of oxygenated (hydroxy) esters of a dimer acid (including linoleic dimer esters of polyhydric alcohols) by the incorporation in the lubricating composition of an C.sub.4 -C.sub.23 oil soluble alkanol or an oil soluble alkyl phosphate. It is disclosed that the selection of the chain length of the alcohol is critical.
European Patent 24,146 relates to lubricating compositions containing oil-soluble copper compounds in an amount sufficient to retard or inhibit oxidation of the lubricant during use (5 to 500 ppm Cu) , and discloses that such lubricant compositions can further comprise from 1 to 10 wt. % ashless dispersant compounds. Preferred are dispersants derived from polyisobutenyl succinic anhydride and polyethylene-amines, which dispersants can be further modified with a boron compound to provide about 0.1 to 10 atomic proportions of boron per mole of the acylated nitrogen compound. In addition, the patent discloses that the lubricant compositions can also contain rust inhibitors such as lecithin, sorbitan monooleate, dodecyl succinic anhydride or ethoxylated alkyl phenols; and other additives such as pour point depressants, viscosity index improvers, other antioxidants (e.g., zinc dialkyldithiophosphates), basic alkaline earth metal detergents, etc. Illustrative of oil-soluble copper compounds are copper dihydrocarbyl thio- or dithio-phosphates, copper salts of a synthetic or natural carboxylic acid (e.g., C.sub.10 to C.sub.18 fatty acids, oleic acid, naphthenic acids) and the like.
U.S. Pat. No. 4,552,677 relates to compositions comprising copper salts of substituted succinic anhydride derivatives containing a hydrocarbon-based substituent group containing from about 8 up to about 35 carbon atoms, which the patentee indicates are effective antioxidants for crankcase lubricants.
U.S. Pat. No. 3,509,052 relates to lubricating oil compositions containing a lubricating oil, a dispersant (which is a derivative of a substituted succinic acid where the substituent contains at least 50 aliphatic carbon atoms), and a demulsifier, e.g., polyoxyalkylene polyols, together with other additives, such as rust inhibitors, oxidation and corrosion inhibitors. The dispersant is said to also permissibly comprise boron post-treated alkyl-substituted succinimides, or metal salts of substituted succinic acids (wherein the metal is preferably a Group I or II metal, Al, Pb, Sn, Co, Ni or Zn).
European Patent 92,946 relates to the combination of oil-soluble copper compounds with glycerol fatty acid esters as fuel economy additives.
U.S. Pat. No. 2,356,661 deals with lubricating oils containing 50 to 100 parts per million of copper together with an oil-soluble organic sulphur compound to provide more stable lubricants which can be employed in internal combustion engines over longer periods of time without causing objectional increase in the viscosity of the oils and with the formation of less deposits in the engine and with less corrosion of sensitive bearing metals. U.S. Pat. Nos. 2,343,756 and 2,356,662 disclose the addition of copper compounds, in conjunction with sulfur compounds, to lubricating oils. In U.S. Pat. No. 2,552,570, cuprous thiophosphates are included in lubricant compositions at relatively high levels, which results in undesirably high sulfated ash content. In U.S. Pat. No. 3,346,493, a wide variety of polymeric amine-metal reactants are employed as detergents in lubricant compositions. In the two isolated instances in which the metal is copper and the composition contains zinc dihydrocarbyldithiophosphate, either the amount of copper employed is outside the range of the present invention or it is necessary that the oil insoluble copper compound be complexed with the dispersant. U.S. Pat. No. 3,652,616 discloses a wide variety of polymeric amine-metal reactants for addition to lubricating compositions. U.S. Pat. No. 4,122,033 discloses the entire group of transition metal compounds as additives for lubricants.
U.S. Pat. No. 3,271,310 relates to metal salts of alkenyl succinic acid, which are disclosed to be useful as detergents and rust inhibitors in hydrocarbon oils and which comprise metal salts of a hydrocarbon substituted succinic acid having at least about 50 aliphatic carbon atoms in the hydrocarbon substituent wherein the metal comprises Group I, Group II, aluminum, lead, tin, cobalt or nickel. The salts are disclosed to be useful in lubricating oils in amounts of from 0.1 to about 20 wt. % and in lubricating compositions for using gasoline internal combustion engines in an amount of from 0.5 to about 5 wt. %. The salts are disclosed to be useful in combination with ashless dispersants, including those which have been borated by reaction with boric acid. Further, the salts are indicated to be useful as emulsifying agents in water in oil emulsions, and that when so employed, other emulsion additives such as rust inhibitors can be used.
U.S. Pat. No. 3,351,647 relates to the phosphorus and nitrogen containing reaction products formed by reacting a metal salt of a phosphinodithioic acid with an amine such as an aliphatic amine having from 1 to about 40 carbon atoms. Copper is among a group of metals disclosed to be useful. The compositions are disclosed as additives for lubricating oils and automatic transmission fluids, in which they act as oxidation inhibitors and anti-wear agents. These compositions are stated to be useful in combination with ashless detergents such as the reaction product of triethylenetetraamine with an alkenyl substituted succinic anhydride having at least 50 carbon atoms in the alkenyl substituent.
U.S. Pat. No. 3,401,185 relates to metal salts of phosphorus acids, including copper salts of such acids, useful in lubricating oils in combination with ashless dispersants which may be borated.
U.S. Pat. No. 3,328,298 relates to metal (e.g., copper) containing compositions formed by reacting a basic inorganic metal compound with an intermediate formed by reacting a phosphorothioic acid diester with an equimolar amount of an epoxide. The resulting metal containing compositions are disclosed to be useful in combination with ashless dispersants.
U.S. Pat. No. 4,417,990 relates to mixed metal salts/sulfurized phenate compositions.
U.S. Pat. No. 4,664,822 relates to certain copper ore based metal containing compositions which are disclosed to be useful in combination with other additives, among which ashless containing dispersants (which can be borated), zinc dialkyldithiophosphates, ash-containing detergents, and ashless rust inhibitors are mentioned.
Canadian Patent 1,189,367 relates to hydrocarbon soluble compositions containing a transition metal salt of an organic acid, a hydrocarbon soluble ashless dispersant and a phenolic antioxidant, which composition can additionally comprise dyes, metal deactivators, and, particularly, demulsifying agents. The transition metal salts mentioned include copper organic salts, and the organic acids include carboxylic acids, sulfonic acids and phosphorus acids It is indicated that the transition metal salts used in the invention are often overbased and contain an excess of one equivalent of metal per equivalent of acid derived moiety.
U.S. Pat. No. 4,552,677 relates to copper salts of hydrocarbyl substituted succinic acids wherein the hydrocarbon group contains from about 8 to about 35 carbon atoms.. Such copper salts are said to be effective antioxidants for crankcase lubricants without the deleterious effect on rust and copper/lead bearing corrosion performance that accompanies copper oleate, which is described in European Patent 24,146, discussed above. The copper salts of the '677 patent are said to be useful in combination with other additives including ashless dispersants which may be borated.
U.S. Pat. No. 4,664,822 relates to lubricating oils compositions comprising ashless dispersant and from 0.1 to 1.5 wt % of a copper overbased metal-containing composition as dispersant/detergent, antioxidant and rust inhibitor additive. It is disclosed that the ashless dispersants may be borated, and that the lubricating compositions can contain additional conventional additives, among which are mentioned friction modifiers. Disclosed as suitable friction modifiers are fatty acid derivatives comprising esters such as triglycerides or monoesters from polyols esters such as glycol monooleate and pentaerythritol monooleate amides such as oleamide or amides made from polyamines or alkanolamines; and hereterocycles made by condensing compounds such as aminoquanidine with carboxylic acids to form triazoles. Further disclosed as suitable friction modifiers are Mo compounds, and combinations of Na sulfonates (or Mo compounds) and glycerol monoleates and other fatty acid derivatives.